Blood autotransfusion involves the collection, filtration, and reinfusion of a patient's own blood. Autotransfusion is a common post-operative practice in those surgical procedures in which it can be expected that there will be post-surgical bleeding. It has become a widely accepted practice in surgical procedures because it avoids the numerous risks associated with transfusion of blood from a third party donor. It is common practice at the end of a surgical procedure to place a drainage tube within the patient at a location where fluids can be expected to pool. The drainage tube exits the surgical wound and is connected to a collection chamber where the blood is collected. Depending on the type of device used, blood may be reinfused into the patient directly from the collection chamber or can be transferred to an intermediate chamber, such as a blood bag, from which it can be reinfused into the patient.
Blood flow into the collection chamber can be induced either by suction developed within the chamber or by positioning the chamber below the wound site to create a gravity head. The suction source may be external, such as directly from the hospital suction system, or from a portable suction device such as that disclosed in U.S. Pat. No. 4,664,652 (Weilbacher). Typically, such autotransfusion devices can be expected to remain connected to the patient during the early part of the patient's recovery, until the surgical site has healed sufficiently so that the volume of recoverable blood is substantially reduced, preferably no more than about six hours in most cases. Depending on the rate at which the patient's fluids may become pooled, it may be necessary to repeat several cycles of collection and reinfuision.
Many autotransfusion devices are designed to operate in an upright position to prevent blood within the collection chamber from being ingested into the suction inlet or leaking out of the collection chamber. Such ingestion or leakage can be expected to affect proper operation of the device. For example, U.S. Pat. No. 4,850,964 (Cotter) illustrates an autotransfusion device having a collection chamber in direct communication with the suction inlet in which blood can be expected to come into direct contact with the suction inlet if the device is placed on or falls on its side. The risk of a vertically placed device being tipped on its side is increased when the patient is being moved from one location (the operating room) to another (the recovery room). It is a common practice with such devices for an attendant to manually carry the autotransfusion device, to maintain it upright while the patient is being moved.
Devices have been proposed and developed to reduce such difficulties. U.S. Pat. No. 5,275,585 (Olson) discloses an autotransfusion system in which the blood collection chamber and suction chamber are isolated from each other. The device has a rigid outer receptacle and a flexible blood collection chamber within the outer receptacle to define an intermediate space between the two. The collection chamber has a blood inlet for receiving blood through a drainage tube from the wound site. The outer receptacle has a port to communicate the intermediate chamber either with ambient air at atmospheric pressure or suction from a suitable suction source. Another approach is incorporated in U.S. Pat. No. 5,374,257 (Drainville) in which an autotransfusion device is provided with a hydrophobic filter between the suction port and the collection chamber to prevent blood in the chamber from being exhausted into the suction source should the container accidentally tip over. That can result in a clogged filter that may impair the efficiency of operation of the device. It is among the general objects of the invention to provide an autotransfusion device having a collection chamber and airflow system that employs a simple, inexpensive arrangement to reduce the risk of blood becoming ingested into the airflow system, not only when the device is upright, but when it is horizontal.
It is desirable that the patient and his surroundings be clean after the conclusion of the surgery when the patient is transferred to his hospital room, not only for aesthetic reasons, but also to avoid disease transmission. A clean appearance is desirable, not only for the patient's comfort, but also for those who visit the patient. It is expected, therefore, that surgical attendants will change the bedding and otherwise clean the patient and his surroundings before returning the patient to the hospital room. When an autotransfusion device has been connected to the patient, the handling of the device during its placement often results in bloody residual fingerprints or smears on the device. That adds to the difficulty in cleaning the patient for optimum post-surgical presentation. It also presents some risk of disease transmission should an unprotected individual come into contact with such residual blood. It would be desirable to provide a blood collection device that simplifies post-surgical presentation of a patient by preventing the unsightly and unsanitary presence of blood on the device.